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sgsnemu: Avoid adding extra autogenerated local link ipv6 addr to tun iface 

It's not needed because a link-local address will be added as a result
of Create Pdp Context Response. Morevoer, it fools sgsnemu ip addr
verifications since it gets used on some scenarios by applications.

Change-Id: I1d51f3ca91edbb3b788939982ab63264182ec2ce
This commit is contained in:
Pau Espin 2020-04-14 18:38:52 +02:00
parent a1503b902c
commit 98f8126b98
1 changed files with 47 additions and 0 deletions
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47
sgsnemu/sgsnemu.c
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@ -46,6 +46,10 @@
#include <resolv.h>
#include <time.h>
#if defined(__linux__)
#include <linux/if_link.h>
#endif
#include "config.h"
#include "../lib/tun.h"
#include "../lib/ippool.h"
@ -999,6 +1003,37 @@ static char *proc_ipv6_conf_read(const char *dev, const char *file)
return proc_read(path);
}
/* write a single value to a /proc file */
static int proc_write(const char *path, const char *value)
{
int ret;
FILE *f;
f = fopen(path, "w");
if (!f) {
SYS_ERR(DSGSN, LOGL_ERROR, 0, "fopen(%s) failed!\n", path);
return -1;
}
if ((ret = fputs(value, f)) < 0) {
SYS_ERR(DSGSN, LOGL_ERROR, 0, "proc_write(%s, %s) failed!\n", path, value);
} else {
ret = 0;
}
fclose(f);
return ret;
}
/* Write value of to /proc/sys/net/ipv6/conf file for given device.
* Memory is dynamically allocated, caller must free it later. */
static int proc_ipv6_conf_write(const char *dev, const char *file, const char *value)
{
const char *fmt = "/proc/sys/net/ipv6/conf/%s/%s";
char path[strlen(fmt) + strlen(dev) + strlen(file)+1];
snprintf(path, sizeof(path), fmt, dev, file);
return proc_write(path, value);
}
static char *print_ipprot(int t)
{
struct protoent *pe = getprotobynumber(t);
@ -1604,6 +1639,7 @@ int main(int argc, char **argv)
struct timeval tv;
int diff;
#if defined(__linux__)
char buf[10];
sigset_t oldmask;
#endif
@ -1668,6 +1704,17 @@ int main(int argc, char **argv)
"Failed to create tun");
exit(1);
}
#if defined(__linux__)
/* Avoid tunnel setting its own link-local addr automatically, we don't need it. */
snprintf(buf, sizeof(buf), "%u", IN6_ADDR_GEN_MODE_NONE);
if (proc_ipv6_conf_write(options.tun_dev_name, "addr_gen_mode", buf) < 0) {
SYS_ERR(DSGSN, LOGL_ERROR, errno,
"Failed to disable addr_gen_mode on %s\n", options.tun_dev_name);
exit(1);
}
#endif
tun_set_cb_ind(tun, cb_tun_ind);
if (tun->fd > maxfd)
maxfd = tun->fd;